That can depend on a lot of factors, like keywords, competition, and search volume.
It's certainly possible to get some search traffic within a few days of publishing. One of my hubs got some visits from Google and Bing in less than a week. The visits were all for longtail keywords, long phrases where there is little targeted competition.
In the long term, however, it can take several months before a hub "matures" and ranks for larger or more competitive keywords. In competitive spaces, linking, social sharing, and other factors are going to help your hub rank above other pages on the Internet - and it takes time for Google to crawl and index all these signals and incorporate them into its search algorithm.
So, in short... for low competition and long tail keywords, you should see some traffic within a week or so. For more competitive keywords, you may not see much for a few months (or ever).